The invention relates to a device for dilution of a sample.
Such devices are used to introduce a diluent liquid to a container containing a sample to obtain a prescribed rate of dilution. The resulting mixture, with the sample optionally crushed previously in another device known as a mixer if the sample is solid, must then undergo microbiological analysis by a laboratory. The device normally comprises a support for receiving a container containing the sample, in which an end piece must dispense the diluent liquid.
Different dilution devices are known. Document EP-A-1 707 939 describes a gravimetric dilution device, in which a pocket of diluent is fixed vertically above the opening of the bag containing the sample. A valve is provided on the lower outlet tube of the pocket for dropping diluent into the bag under the control of a control circuit.
U.S. Pat. No. 4,350,186 describes a device for dilution of a sample in a container, for sending diluent liquid to the container via a first rapid valve and a second slow valve supplied with diluent by a tank via a pump. The valves are supported above the container by a metal bar and a horizontal member, the container being arranged on a base comprising a weighing system. The device also comprises a controller having a locking line which is coupled to an interrupter, which is fixed to the chassis of the base and which enables the valves fixed to the horizontal member to operate when the bar is rotated such that the interrupter is closed and the valves are above the container.
Also, devices other than devices for dilution of a sample are also known. Document EP-B-1 029 808 concerns a distribution head for a liquid product, for example a cosmetic substance, in which it is the user who must manually turn positioning means to be able to press on a push-button which is to control opening of a distribution valve of the product. Document WO-2007/113 561 describes a device for preparation of samples using a syringe fixed on a support and actuated by a motor mounted on the support.
U.S. Pat. No. 2,853,210 concerns a device for distribution of liquid from a bottle with an external body which a user must turn manually relative to an internal body to pass between a distribution position and a closed position. Document FR-A-2 579 749 describes an automatic device for sampling and dilution of a liquid product circulating continuously in circuits. Document EP-B-0 251 744 concerns a device for distribution of a fluid, comprising two pumps fixed on the cover of a container, one of which comprises a motor for incrementally metering a specific volume of fluid to be supplied.
An aim of the invention is, in a device for dilution of a sample, to make for easy handling both of the container containing the sample and of the device for introducing the diluent thereto. Another aim is, in a device for dilution of a sample, to prevent the end piece for distribution of the diluent to be contaminated by the sample liquid or by particles of the sample when the dilution operation in the container is completed and when the container has to be withdrawn, due to the fact that the diluent liquid reaches a certain level in the container. Another aim is to improve the ergonomy of the device for dilution of a sample. Another aim is to reduce production costs of the device for dilution of a sample.
The aim of the invention is a device for dilution of a sample, comprising:
at least one support provided on a base for receiving a container having to contain the sample and comprising an upper opening,
at least one end piece for distribution of a liquid diluent, comprising an outlet for the diluent,
a system for conveying of the diluent in the end piece according to a determined quantity, fitted with control means,
means, comprising an upright extending up from the base, for supporting and shifting the end piece relative to the container support between one and the other of a first position, in which the outlet of the end piece is above the opening of the container to enable the diluent to be sent to the container via the end piece, and of a second position, in which the outlet of the end piece is further away from the container than in the first position, characterised in that the second position of the outlet of the end piece is lateral relative to its first position, the upright is fixed on the base relative to the container support, the upright is topped by a cover serving as support of the end piece, the cover being mounted rotatively on the upright between one and the other of the first and second positions, a rotary motor for rotating the cover between one and the other of the first and second positions being housed inside the cover and/or of the upright.
According to embodiments of the invention:
The motor is located in the upper part of the upright under the cover.
The cover comprises an external surface located opposite the external surface of the upper part of the upright.
The end piece has its outlet bent relative to its part serving to attach it to the cover.
The cover comprises at least one member for detachable attachment of the end piece, this attachment member also acting as rotation connection of the cover to the motor.
The motor is capable of turning an axle made solid in rotation with the cover by coupling means for turning the cover and the end piece between one and the other of the first and second positions.
The coupling means comprise a piece fixed on the axle, the cover comprising means for detachable attachment of the end piece, serving also as attachment to the piece fixed to the axle.
The cover comprises first and second stops cooperating with at least one stop member fixed relative to the upright for stopping the rotation of the cover respectively in the first and second positions by support of the stop member respectively against the first and second stops.
The device comprises means for detecting approach of the first position and/or of the second position cooperating with automatic control means for stopping rotation of the motor before the stop member touches the associated stop.
The means for detecting approach are optical for detecting the presence of a hole or wall located in the cover, such that detection of an edge delimiting the hole and the wall corresponds to an angular position of the cover located close to the first and/or second position without the stop member touching the associated stop.